Hi folks,

I have 4 checkboxes, a button and a div.

The checkboxes are unchecked, the button is disabled and the div opacity is '0.1'.
When all checkboxes are checked, the button should be enabled, and when the button is clicked, div opacity should be '0.9'.

I need help in enabling the button. Here's my code: http://jsfiddle.net/HzCvt/3/
Please, have a look and tell me where I went wrong.

Thank you!